## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - The issue detail page is a core operator surface where perceived
latency directly affects task navigation
> - Performance work needs repeatable evidence so later optimizations
can be compared against the same scenarios
> - The page did not expose stable user-timing marks for its header or
first useful content
> - There was also no isolated seeded browser rig that measured warm
navigation, cold deep links, waterfalls, or server time
> - This pull request adds the instrumentation and a one-command
Playwright baseline harness
> - The benefit is that issue-page performance changes can be validated
with reproducible median measurements instead of anecdotes
## Linked Issues or Issue Description
**Subsystem affected**
Cross-cutting: `ui/`, `server/`, and browser performance tooling.
**Problem or motivation**
The issue detail page performs a large client bootstrap and request
fan-out, but the repository lacks stable user-timing boundaries and a
repeatable benchmark. That makes performance changes difficult to
compare and allows regressions to be judged from anecdotes instead of
consistent evidence.
**Proposed solution**
Add stable header/content paint measures, development/QA-only lifecycle
vital reporting, aggregate server timing for the issue endpoint, and a
seeded Playwright command that runs warm/cold scenarios under throttled
and unthrottled profiles with N≥5 median reporting.
**Alternatives considered**
Ad hoc DevTools recordings were rejected because they are not repeatable
or reviewable. Production telemetry was rejected because this baseline
should not change production data collection. A unit-only harness was
rejected because it cannot capture browser bootstrap, rendering, and
network waterfall costs.
**Roadmap alignment**
The roadmap calls for agent performance to be measurable over time. This
change applies that evidence-first principle to a core operator page and
does not duplicate a listed roadmap deliverable.
**Additional context**
The generated report includes warm and cold medians, TTFB/FCP/LCP where
applicable, request and byte totals before first useful content,
JavaScript bytes, and issue endpoint server timing.
## What Changed
- Added `issue-detail:navigate→header-paint` and
`issue-detail:navigate→content-paint` user-timing measures to the issue
detail page.
- Added development/QA-only TTFB, LCP, and INP console reporting without
production telemetry delivery.
- Added `Server-Timing` for `GET /api/issues/:id`.
- Added `pnpm exec playwright test --config
tests/perf/issue-detail/playwright.config.ts`, which seeds an isolated
instance and runs N≥5 warm/cold samples under unthrottled and Fast 4G/4x
CPU profiles.
- Added Markdown, raw JSON, and Chrome-trace outputs with median
baseline tables and waterfall data.
## Verification
- `pnpm --filter @paperclipai/ui typecheck`
- `pnpm --filter @paperclipai/server typecheck`
- `pnpm check:token-gates`
- `npx playwright test --config
tests/perf/issue-detail/playwright.config.ts --list`
- `pnpm exec playwright test --config
tests/perf/issue-detail/playwright.config.ts` — passed 20 samples in 9.4
minutes (5 runs × 2 scenarios × 2 profiles) for the baseline;
post-review integrity reruns also exercised the corrected paths, while
this shared runner intermittently killed Chromium processes, so the rig
now performs one bounded browser-crash retry per sample.
- Baseline medians: warm unthrottled 278/447 ms header/content; cold
unthrottled 646/646 ms; warm throttled 1240/2060 ms; cold throttled
3932/3933 ms.
## Risks
- Low product risk: the new browser measurements are development/QA
tooling and the UI timing work does not change visible layout.
- `Server-Timing` exposes only aggregate handler duration, not query
contents or private identifiers.
- Native INP reporting uses supported browser event timing entries and
silently no-ops where unsupported.
> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.
## Model Used
- OpenAI Codex, GPT-5.4, tool-assisted coding and browser execution with
reasoning enabled; context-window size is not exposed in this
environment.
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
---------
Co-authored-by: Paperclip <noreply@paperclip.ing>
Co-authored-by: Dev Agent <dev@paperclip.ing>
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